Couplers are widely used in the construction industry, more specifically in the earth moving industry, in combination with excavating equipment such as excavators and backhoes to enable excavating equipment to be used with a variety of tools. Thus, a good coupler can greatly expand the utility of a single piece of equipment. For example, a backhoe fitted with a coupler can be interchangeably equipped with shovels, ripper tooths, hydraulic hammers and the like thereby diversifying the uses of the backhoe.
An important characteristic of a coupler is the amount of time required to detach and attach the construction implements thereto. This amount of time is usually referred to as downtime. Downtime can be greatly minimized by employing quick couplers, i.e., couplers which can be quickly attached to and detached from the implement without having to do so manually, as opposed to couplers which require a worker, for example, to remove and attach implements to a coupler by hand. U.S. Pat. No. 5,082,389 to Balemi, the disclosure of which is incorporated herein by reference, discloses such a quick coupler.
Another important characteristic of a coupler is the manner in which the coupler attaches to an implement. Quick couplers, such as disclosed in Balemi, typically rely on two recesses in the coupler for receiving a pair of machine pins of the implement. A single closure member is associated with one of the recesses for locking one of the pins within one recess. The second machine pin is indirectly held within the second recess by the action of the closure member associated with the first recess. Accordingly, only one of the pair of machine pins is structurally locked within a recess.
FIGS. 1 and 2 show another prior art quick coupler, namely, the JB Quick Coupler manufactured and sold by Hendrix Manufacturing Company, Inc. of Mansfield, La., the owner of the present invention. FIG. 1 shows the coupler in the open position, or before attachment of the implement, and FIG. 2 shows the coupler in the closed position, or after the implement is attached. This JB Quick Coupler, which has been quite successful, generally comprises a body having two recesses for receiving the machine pins of the implement, a locking lever and a hydraulic cylinder for actuating the locking lever. More specifically, it includes a pair of opposed, parallel side plates 2 having a front 3 and a rear 5. Side plates 2 are interconnected and held in parallel relation by a flat, rectangular transverse plate 4 suspended between and attached at each respective end thereof to side plates 2 near the rear of the coupler. A forward-facing, C-shaped transverse plate 6 is suspended between and attached at each respective end thereof to side plates 2 near the front 3 of the coupler. C-shaped transverse plate 6 defines an open, forward-facing recess 7 in the front of side plates 2.
Interposed between side plates 2 and transverse plates 4 and 6 there is a rear-facing locking lever 8 pivotally attached to side plates 2 by a pin 9. Locking lever 8 is arranged to pivot rearward to block an open, downward-facing recess 10 which is defined at each end thereof by a notch 11 in each of side plates 2 near the rear of the coupler. Locking lever 8 is pivoted by an actuator 12, such as an hydraulic cylinder.
More particularly, side plates 2 of the JB Quick Coupler comprise a pair of opposed upper plates 14 having a pair of spaced-apart apertures 16 which provide a means of attaching the quick coupler to the boom of a piece of equipment and a pair of opposed lower plates 18 welded thereto which include rear recess 10 and front recess 7. Recesses 7 and 10, in combination with locking lever 8 and actuator 12, provide a means of attaching an implement to the coupler. Specifically, as illustrated in FIGS. 1 and 2 locking lever 8 is arranged to pivot down and rearward when urged by actuator 12 to lock a machine pin of the implement in place in recess 10.
To employ the JB Quick coupler, the coupler is first manually attached to the end of a boom (not shown) of a piece of equipment by inserting locking pins through apertures 16 in upper plates 14 and concurrently through a set of complementary apertures in the boom. Next, the quick coupler is maneuvered, while in an open position as illustrated in FIG. 1, over an implement and lowered so that one of a pair of machine pins of the implement is positioned within recess 7. The rear of the coupler is then tilted downward so that the other machine pin of the implement is maneuvered into recess 10. As illustrated in FIG. 2, closure member 8 is urged down and rearward by an actuator rod 19 of actuator 12 into recess 10 to lock the machine pin of the implement within recess 10. Compression springs (not shown) are included on each lateral side of actuator rod 19 to act as a redundant safety back-up for closure member 8 in the event actuator 12 fails. To detach the implement from the coupler, closure member 8 is simply urged forward and up, away from recess 10, freeing the attachment rod seated therein.
The JB Quick Coupler has performed well in the field. However, Hendrix Manufacturing, the assignee of this invention, has sought to further improve quick couplers as described hereafter.